1. Field of the Invention
The present invention relates to multilayer coil components, particularly to a multilayer coil component including two helical coils electrically connected to each other in parallel and laminated in a laminated body.
2. Description of the Related Art
Conventionally, a multilayer coil component described in Japanese Unexamined Patent Application Publication No. 6-196334 has been known. As shown in FIG. 8, the multilayer coil component 71 has a configuration in which a first coil unit 78 is stacked on a second coil unit 79, each coil unit including laminated ceramic sheets 72 provided with coil conductors 73a to 73e and via-hole conductors 75. The coil conductors 73a to 73e are mutually connected in series via the via-hole conductors 75 so as to form helical coils 73A and 73B. The two helical coils 73A and 73B are electrically connected to each other in parallel so as to form a multilayer coil component having a large withstand current value.
In the multilayer coil component 71, however, the two helical coils 73A and 73B have the same pattern and the same number of turns. Thus, if the number of turns is changed to adjust inductance, the number of turns increases or decreases in the two helical coils at the same time. This causes a significant change in inductance and a problem that fine adjustment of inductance is difficult.
As shown in FIG. 9, when a multilayer coil component 81 having a configuration in which coil conductors 73e and 74a of a large number of turns face each other is fabricated for the purpose of strengthening the coupling between two helical coils 73A and 74A, coil conductors of patterns denoted by numerals 74a to 74e need to be newly formed. That is, the positions of the via-hole conductors 75 are different in the same patterns of coil conductors, and thus, the types of patterns of the coil conductors increase disadvantageously.